1. Field of the Invention
The present invention is directed to an improved polymer and method to make it, more particularly the invention relates to an polymer having at least one carbon-carbon double bond reacted, according to the Koch reaction mechanism, with carbon monoxide in the presence of an acidic catalyst to form a carbonyl or thiocarbonyl functional group, and derivatives thereof.
2. Description of Related Art
For the purpose of the present invention the term "polymer" is defined as a large molecule built up by the repetition of small, simple chemical units. (Billmeyer, J. R., Textbook of Polymer Sciences, 2nd Ed., J. Wiley p.3 (1971). Polymers are considered to be defined by average properties, and shall be considered to have a number average molecular weight of at least 500.
For the purpose of the present invention the term "hydrocarbon" refers to a compound comprising hydrogen and carbon which has specific or precise properties (i.e., molecular weight) in contradistinction to polymeric materials which have average properties such as average molecular weight. However, the term "hydrocarbon" is not intended to exclude mixtures of different materials which individually are characterized by such specific and precise properties. Both hydrocarbon compounds as well as polymeric compounds have been reacted to form carboxyl group containing compounds and their derivatives. Carboxyl groups have the general formula ##STR1## where R can be H, a hydrocarbyl group or a substituted hydrocarbyl group.
The synthesis of carboxyl group containing compounds from olefinic hydrocarbon compounds, carbon monoxide and water in the presence of metal carboxyls is disclosed in references such as N. Bahrmann, Chapter 5, Koch Reactions, of the text "New Synthesis with Carbon Monoxide" edited by J. Falbe; Springer-Verlag, New York, N.Y. 1980. In accordance with the disclosed Koch reactions, hydrocarbon compounds having olefinic double bonds are disclosed to react in two steps to form carboxylic acid-containing compounds. In the first step an olefin compound reacts with an acid catalyst and carbon monoxide in the absence of water. This is followed by a second step in which the intermediate formed during the first step undergoes hydrolysis or alcoholysis to form a carboxylic acid or ester. An advantage of the Koch reaction is that it can occur at moderate temperatures of -20.degree. C. to +80.degree. C., and pressures up to 100 bar.
Bahrmann et al. disclose a mechanism for a Koch reaction wherein an olefinic hydrocarbon compound is reacted with an acid catalyst and carbon monoxide. A hydrogen compound having the formula: EQU R(CH.sub.3)C.dbd.CH.sub.2
is reacted with an acid such as sulfuric acid and carbon monoxide. Initially, a carbenium ion forms having the formula: EQU R(CH.sub.3).sub.2 C.sup.+
The carbenium ion reacts with carbon monoxide (CO) to form an acylium cation having the formula: EQU R(CH.sub.3).sub.2 C--CO.sup.+
The acylium cation can then be hydrolyzed with an alcohol or water to form an ester or an acid having the formula: EQU R(CH.sub.3).sub.2 C--COOR'
where R is a hydrocarbon and R' is H or a hydrocarbon.
The Koch reaction can occur at double bonds where at least one carbon of the double bond is di-substituted to form a "neo" acid or ester (i.e. ##STR2## Bahrmann et al. discloses isobutylene converted to isobutyric acid via a Koch-type reaction. The Koch reaction can also occur when both carbons are mono-substituted or one is monosubstituted and one is unsubstituted to form an "iso" acid (i.e. R.sub.2 HC--COOR).
U.S. Pat. No. 2,831,877 discloses a multi-phase, acid catalyzed, two-step process for the carboxylation with carbon monoxide of olefins such as ethylene, propene, butene, isobutene or higher molecular weight olefins such as nonene, hexadecene and the like. This early reference points to considerations including yield and catalyst separation from the product. Disclosed catalysts include Broensted acids such as H.sub.2 SO.sub.4, HF, H.sub.3 PO.sub.4 as well as Broensted acids used in combination with Lewis acids. Useful Lewis acids include BF.sub.3. It is disclosed that a system of BF.sub.3.H.sub.2 O and methanol usually requires around 100 bar and temperatures of 100.degree. C. Milder conditions are reported with H.sub.2 SO.sub.4 and H.sub.3 PO.sub.4 (25/100 bar CO pressure and 20.degree./100.degree. C.). Very mild conditions are disclosed with HF. Good yields are reported for methyl esters obtained in the presence of BF.sub.3.CH.sub.3 OH. It is reported that depending on the weight ratio of BF.sub.3 to H.sub.2 O the system can be homogeneous (ratio 1:1) or heterogeneous (ratio 1:2). The heterogeneous system has been reported to exhibit higher activity.
U.S. Pat. No. 2,967,873 to Koch et al. is directed to a process for the production of aliphatic and cycloaliphatic monocarboxylic acid alkyl esters. The process entails the exposure of an olefin and carbon dioxide to the presence of a catalyst. The catalyst disclosed is a mixture of a hydroxy fluoroboric acid and an alkoxy fluoroboric acid. The background of this patent discloses that catalysts including monohydroxy fluoroboric acid as well as the hydronium salt of this acid have been used. The olefinic materials described include a variety of materials including 2-methylpent-1-ene, diisobutene, isododecene, isopentadecene, and isononene prepared by polymerization of propene, olefins from the cleavage of oil products, and also dimers produced by the process of K. Ziegler. Alcohols useful in the method disclosed include methanol, ethanol and then propanol.
Complexes of mineral acids in water with BF.sub.3 have been studied to carboxylate olefins. U.S. Pat. No. 3,349,107 discloses processes which use less than a stoichiometric amount of acid as a catalyst. Examples of such complexes are H.sub.2 O.BF.sub.3.H.sub.2 O, H.sub.3 PO.sub.4.BF.sub.3.H.sub.2 O and HF.BF.sub.3.H.sub.2 O.
Sulfuric acid is known to be used as a catalyst in Koch reactions as disclosed in Bahrmann, cited above. Bahrmann refers to Y. Komatsu et al., Maruzen Sekiyo Gihi 21, 51 (1976) regarding the use of 85% sulfuric acid as a catalyst for carboxylation of tertiary olefins in the presence of trichloroethylene as a solvent. Chlorinated solvents are used to isolate the neo acid in the acid mixture. Other disclosures using sulfuric acid include the use of mixtures of phosphoric and sulfuric acids as catalysts especially in the presence of copper salts, H. Kawasaki et al., J62164-645-A. The sulphonate which forms is disclosed to result in color, odor and acid quality problems and can be inhibited by the disclosed procedure. The presence of substantial quantity of phosphoric acid in the catalyst also induces phase separation in the product/catalyst recovery step.
Ya Eidus et al., Z. Org. Chem. 4 (3) 376 (1968) discloses the use of phosphoric acid as a catalyst system which permits phase separation of the reaction products. However, the application of pure H.sub.3 PO.sub.4 compared to H.sub.2 SO.sub.4 necessitates more severe reaction conditions (75/200 bar instead of 70/80 bar and 125.degree./150.degree. C. instead of 10.degree./50.degree. C.). Bahrmann discloses that H.sub.3 PO.sub.4 /BF.sub.3 permits excellent separation of reaction products.
Hydrogen fluoride, HF, catalyst has been disclosed to be used in pure form as well as in an aqueous solution. Yields of greater than 95% have been obtained at high catalyst concentrations HF:olefin:H.sub.2 O of 10:1:1. The low boiling point of hydrogen fluoride has been suggested to be an advantage for catalyst separation via pressure distillation. References such as U.S. Pat. No. 3,527,779 suggest that acid strength of the catalyst has a marked effect on the rate and selectivity of the Koch reaction. Examples of acid strength on the selectivity of pivalic acid are disclosed in the '779 patent. Strong acid catalysts promote the isomerization of linear unbranched olefins (carbon number greater than or equal to 4) to form highly branched unsaturates. This is particularly relevant to the Koch reaction since by proper control of reaction conditions it is possible to carboxylate linear olefins to form iso acids. The use of more severe reaction conditions promotes isomerization of the carbon backbone which, followed by carboxylation, results in the formation of neo acids.
Temperature and pressure are disclosed by Bahrmann to affect the reactants, intermediates and final products in the Koch reaction. An increase in reaction temperature generally has a favorable effect on neo acid yield. The magnitude of the temperature effect on selectivity depends on the acid strength of the catalyst with the weaker the catalyst the stronger the temperature effect. It is disclosed that the position and rate of attainment of equilibrium of the following reactions are determined by the temperature: dehydration/hydration esterification/saponification (with alcoholic starting materials); isomerization of the carbenium ions; oligomerization/depolymerization of carbenium ions; and carboxylation/decarboxylation.
Bahrmann et al. disclose that, generally higher yields and more uniform products are achieved at high CO pressures. This is due to the trapping of the carbenium ion (via transformation into acyl complexes) which supresses the isomerization and oligomerization thereby preventing the formation of a series of by-products.
High levels of CO and sulfuric acid can be obtained by the addition of anhydrous formic acid to the reaction median. Formic acid decomposes in strong acid at room temperature to form CO and water. The rate of decomposition of formic acid is acid strength dependent.
The amount of stirring can affect the yield of carboxylic acids in a Koch-type reaction mechanism using formic acid as a CO source. Less stirring results in more secondary carbenium ions resulting in iso-carboxylic acids. It has also been reported that the conversion of 1-hexene in the presence of BF.sub.3.H.sub.2 O resulted in increased neo acid content in the product increased on raising temperature from 20.degree. C. to 100.degree. C. and on decreasing CO pressure from 85 to 27 bar (Gushcin, et al.; Neftekhimiya 12 (3) 383 (1972), Chem. Inf. 41 (1972) which was referred to in Bahrmann).
Other considerations reported by Bahrmann et al. which can determine the outcome of a Koch reaction include the catalyst to olefin mole ratio, the product and catalyst recovery, and the reactor throughput and residence time.
The use of a solvent can affect product/catalyst recovery. However, Onopchenko, A. et al., DE2811867 (Mar. 18, 1978) disclose that with higher alpha olefins (greater than 16 carbons in length), higher yields of carboxylic acids were obtained in the absence of a solvent. Disclosed solvents for use in Koch systems include saturated hydrocarbons such as n-heptane, cyclohexane, methylcyclohexane, isooctane, benzene, chlorobenzene, chloroform, trichloroethylene, tetrachloroethylene, methylene chloride, trifluoro and trichloro ethane, carbon tetrachloride, fluorobenzene or mixtures thereof.
European Patent Publication No. 0,148,592 relates to the production of carboxylic acid esters and/or carboxylic acids by catalyzed reaction of a polymeric hydrocarbon having carbon-carbon double bonds, carbon monoxide and either water or an alcohol, optionally in the presence of oxygen. The catalysts can be selected from metals such as palladium, rhodium, ruthenium, iridium, and cobalt in combination with a copper compound. The reaction is conducted in the presence of a protonic acid which can include hydrochloric acid, sulfuric acid or an organic acid which can be a carboxylic acid. The reaction using transition metal catalysts is described as an oxycarbonylation, (see, for example, Wender, I, Organic Synthesis via Metal Carbonyls, Volume 2). Useful alcohols are disclosed in '592 to include R.sub.2 CHOH, wherein R is independently hydrogen, alkyl, aryl, or hydroxyalkyl or the two groups R together form a ring. The carbon monoxide pressure may be the autogeneous pressure at the reaction temperature of 2 to 250 psig above autogeneous pressure. The reaction can be conducted in the presence or absence of oxygen with oxygen preferred for improved yields. Optionally, and preferably, hydrocarbon solvents are used. The reaction is conducted at from 20.degree. to 150.degree. C. for 30 minutes to 8 hours. A preferred polymer is indicated to have at least 80% of its carbon-carbon double bonds in the form of terminal double bonds. Example polymers include butene polymers, ethylene copolymers and terpolymers, and vinyl aromatic diene copolymers. The polymeric compound containing a carbon-carbon double bond can be a hydrocarbon polymer containing greater than 20, for example, greater than 30 carbon atoms. A disclosed polymer is butene polymer, a preferred butene polymer is known as polyisobutylene, sometimes referred to as polyisobutene (PIB) which can be a low to medium molecular weight liquid product obtained from polymerization of at least partially purified isobutylene feeds. Examples of suitable polyisobutylenes include liquid polyisobutylenes having a number average molecular weight in the range of from 200 to 2,500, preferably up to 1,000.
U.S. Pat. No. 4,681,707 relates to a process for the production of carboxylic acid ester and/or a carboxylic acid which process comprises reacting an unsaturated hydrocarbon with carbon monoxide and either an alcohol or water in the presence of a protonic acid and a catalyst. The catalyst system and the alcohol are the same as disclosed in EP No. 0,148,592 referred to above. The carboxylic acid is produced from an unsaturated compound containing 2 to 30 carbon atoms.
U.S. Pat. No. 4,902,822 discloses a process for the preparation of carboxylic acids or of esters thereof by contacting an olefinic unsaturated compound with carbon monoxide in the presence of water or an alcohol, respectively, and of a catalytic system prepared by combining a ruthenium compound and a compound having a non-coordinating ion of an acid with a pK.sub.a below 0.5. The olefinic compounds are disclosed to have from 2 to 30 carbon atoms. The non-coordinating anion is of an acid which can include sulfuric acid, sulfonic acid, or of an acid that can be formed by interaction of a Lewis acid with a Broensted acid. Examples of such Lewis acids include BF.sub.3. The alcohols which are used are disclosed to include aliphatic, cycloaliphatic or aromatic and may be substituted with one or more substituents. The alcohol may include a phenol, including alkyl substituted phenol.
U.S. Pat. No. 4,927,892 relates to reacting a polymer or copolymer of a conjugated diene at least part of which is formed by 1,2 polymerization wherein the .alpha.-carbon to the carboxyl group is unsubstituted with carbon monoxide and water and/or alcohol in the presence of a catalyst prepared by combining a palladium compound, certain ligands and/or acid except hydrohalogenic acids having a pk.sub.a of less than 2. Useful Lewis acids include BF.sub.3.
U.S. Pat. No. 4,312,965 relates to a process of forming polymeric polyamines/amides by reacting an olefinic polymer derived from monomers having multiple olefinic double bond, with carbon monoxide, water and ammonia or amine in the presence of a rhodium catalyst.
The reaction at olefinic sites on hydrocarbons with carbon monoxide and water has been addressed in U.S. Pat. No. 3,059,007. This reference relates to improvements in the production of carboxylic acids from monoolefins, carbon monoxide and water. The reaction is conducted at a temperature of -25.degree. C. to 100.degree. C., at a pressure of 20 to 150 atmosphere in the presence of a highly acidic inorganic catalyst. The only disclosed catalyst was a mixture of H.sub.3 PO.sub.4, BF.sub.3 and water in a molar ratio of 1:1:1. The olefins are disclosed to have at least three carbons. The acid formed is secondary or tertiary. Available unsaturated charge materials comprise unsaturated hydrocarbons, particularly monoolefins such as propylene, butylene-1, butylene-2, isobutylene, branched or unbranched pentenes, hexenes, heptenes, octenes, nonenes, decanenes and high alkenes. Diisobutylene, propylene tetramer; cycloalkenes such as cyclopentenes and cyclohexenes are characterized as useful polymers and copolymers.
U.S. Pat. No. 3,992,423 is directed to the production of carboxylic acids from olefins with a catalyst comprising a zeolite in an aluminum hydrosol. In particular, carboxylic acids are prepared by a process which comprises the treatment of an unsaturated hydrocarbon with a compound containing a hydroxy group and carbon monoxide in the presence of the zeolite catalyst.
Puzitskii et al., Carbonylation of Olefins and Alcohols With Carbon Monoxide in the presence of a Catalyst System: BF.sub.3.H.sub.2 O-liquid SO.sub.2, N. D. Zielinski, Institute of Organic Chemistry, Academy of Sciences of the U.S.S.R., Moscow, translated from Izvestiya Academii Nauk SSR, Seriya Khimicheskaya, No. 10, pp. 2331-2334, October, 1977. Original article submitted Jan. 4, 1977, published by the Plenum Publishing Company, 1978. This article discloses that it was known that olefins, with branching at the double bond, and tertiary alcohols in a mixture with methanol or ethanol are selectively carbonylated to esters under mild conditions (-70.degree. C., atmospheric pressure) in the presence of the catalyst system SbCl.sub.3 --HCl-liquid SO.sub.2. The Puzitskii paper discloses that branched hydrocarbon olefins and tertiary alcohols are easily carbonylated under mild conditions (-30.degree. C., atmospheric pressure) in the presence of the catalyst system BF.sub.3.H.sub.2 O-liquid SO.sub.2. Liquid SO.sub.2, as a solvent with a high dielectric constant facilitates the formation of carbenium and acylium ions from olefins or alcohols and CO. Liquid SO.sub.2 has been found to have an effect on CO by facilitating its polarization and activity.
U.S. Pat. No. 4,262,138 discloses a process wherein ethylene or propylene are carbonylated with carbon monoxide to form carboxylic acid esters in the presence of a catalyst complex of one mole of BF.sub.3 and one mole of alcohol.
U.S. Pat. No. 4,256,913 discloses that propylene and ethylene may be carbonylated to form carboxylic acids or carboxylic esters in the presence of a catalyst complex containing one mole of BF.sub.3 and one mole of a second complexing component. In the case of the formation of the ester, the second complexing component is an alcohol, while in the case of the preparation of carboxylic acid, the second complexing component is water. It is disclosed that isobutyric acid and propionic acid formed from propylene and ethylene, respectively, in the presence of BF.sub.3.H.sub.2 O catalyst may be dehydrogenated to prepare methacrylic acid and acrylic acid respectively.
U.S. Pat. No. 4,717,755 describes production of a propylene homopolymer or copolymer having a terminal carboxyl group by polymerizing with V(aceylacetonate).sub.3 and Al(C.sub.2 H.sub.5).sub.2 Cl and terminating the polymerization with carbon monoxide.
U.S. Pat. No. 4,704,427 teaches a method of modifying a rubber including subjecting the rubber to a carboxylation with, inter alia, carbon monoxide in the presence of a metal carbonyl compound. Chemical Abstracts '77 (12) 76298 likewise discloses a method of reacting a rubber with carbon monoxide in the presence of a metal carbonyl compound to introduce carboxyl groups into the rubber.
U.S. Pat. No. 4,980,422 teaches functionalizing a polymerized conjugated diene by contacting it with carbon monoxide and an alcohol in the presence of a catalyst comprising an amine ligand and a cobalt compound. The polymers formed having appended ester groups or terminal carboxyl groups when the o-carbon carboxyl group is unsubstituted.
U.S. Pat. No. 4,798,873 relates to carboxylic acid functionalized polyolefins prepared by olefin polymerization using organometallic catalysts followed by carbonylation with CO.sub.2.
Other disclosures of interest include U.S. Pat. Nos. 4,929,689; 4,539,654; 3,910,963; 4,323,698; 4,224,232; 3,870,734; 4,717,755; 4,518,798; 2,586,070 and Japanese Ref. 51-41320.
Polymers functionalized with carboxylic acid, ester and the like groups, are useful for a variety of purposes. For example, U.S. Pat. No. 3,903,003 teaches the use of a terminally carboxylated, substantially completely hydrogenated polyisoprene which is reacted with a polyalkylene amine or hydroxyl polyalkylene amine and formed into a lubricating composition. There is particularly disclosed a polymerization of isoprene using a lithium based initiator. The polymer produced is referred to as a living polymer with the end of the polymer chain associated with the lithium radical. The lithium polymer is subjected to carboxylation such as by reaction with carbon dioxide to form a polyisoprene having a terminal carboxyl group.
U.S. Pat. No. 4,857,217 teaches a dispersant additive which is an adduct of (a) a polyolefin substituted with dicarboxylic acid producing moieties and (b) an amidoamine or thioamidoamine. A functionalized polymer which was used in the foregoing dispersant and lubricant compositions is an alkenyl succinic anhydride produced by reacting maleic anhydride and polyisobutylene. The polymer to be substituted with the dicarboxylic acid is described as a polyolefin polymer or copolymer which can be made by a variety of means and reacted with a C.sub.4 to C.sub.10 unsaturated dicarboxylic acid, anhydride or ester. The olefin and dicarboxylic acid material can be reacted by simply heating together, as disclosed in U.S. Pat. Nos. 3,361,673 and 3,401,118, to cause a thermal "ene" reaction to take place. Alternatively, the olefin polymer can first be halogenated, for example, chlorinated or brominated at a temperature of from 60.degree. C. to 250.degree. C. The halogenated polymer can then be reacted with sufficient unsaturated acid or anhydride so that the product obtained will contain the desired number of moles of unsaturated acid per mole of halogenated polymer. There is no disclosure of reacting an unsaturated polymer in accordance with Koch-type chemistry to incorporate a carboxyl group.